Deployment of cables for landing strings

ABSTRACT

Embodiments may generally take the form of a cable winch system installable within a riser on a landing string. In particular, one embodiment may take the form of a system having a tubular deployable within a riser and a cable winch deployable within a riser. The cable winch is configured to travel with the tubular as it is deployed within the riser.

BACKGROUND

Generally, landing string systems are used during completion of offshorewells and are deployed into a drilling riser using an umbilical. Thefluids, electrical power and communications services from the surfacevessel or rig to the landing string are transmitted via this umbilical.As such, the umbilical includes hoses, electrical cables andcommunications cables. These landing string systems also may include ahydraulic power unit located on the surface support vessel. Theumbilical is stored on a storage reel that is used to deploy theumbilical in the riser from the drilling rig. The umbilical is fed intothe riser during deployments so that it can slide on parts of the rig asit is being deployed. The umbilicals are clamped onto the landing stringtubular members during deployment as they cannot be deployed undertension due to the nature of their construction. Deploying and clampingthe umbilical on the tubulars is a time consuming phase of thedeployment operation and results in increased rig time. Additionally,locating the umbilical reel on the rig may present installation issues,many times requiring sheaves to be located in the tower to provide apath for the umbilical from the reel to the rig floor.

SUMMARY

Embodiments may generally take the form of a cable winch systeminstallable within a riser on a landing string. In particular, oneembodiment may take the form of a system having a tubular deployablewithin a riser and a cable winch deployable within a riser. The cablewinch is configured to travel with the tubular as it is deployed withinthe riser.

Another embodiment may take the form of a method of providing subseacommunications. The method includes securing a cable winch to a subsealanding string, securing a cable wound on the cable winch at a surfacelocation and deploying the subsea landing string.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example landing string system with conventionalhardware.

FIG. 2 illustrates a cable winch system deployable as part of thelanding string system of FIG. 1.

DETAILED DESCRIPTION

A cable winch system is disclosed that may be installed on a landingstring. The winch system contains a cable that is stored and deployedfrom the landing string, as it is lowered into the riser. In the system,no cable storage reel or winch on the surface is used. Additionally, thesystem may be implemented without sheaves and/or clamping on thetubulars during deployment, reduces occupied deck space, and helpsprevent cable damage during deployment, subsea operations and retrievalof the landing string.

The disclosed cable winch system provides a hard wired connection thatcan function as a backup to an umbilical-less communication system ormay be used as a primary communication mode. Transmission through thecable provides rapid communication between the landing string and thecontrol system.

Turning to the drawings and referring initially to FIG. 1, a subsea testtree system 100 is illustrated. The system 100 may include surfacecomponents and subsurface component. For the sake of conciseness, notall the surface or subsurface components are described and/orillustrated. Additionally, the specific function of the components maynot be discussed in detail, but would be understood and appreciated bythose skilled in the art. In an actual implementation, more, fewerand/or different components may be used. As such, the system 100 isprovided as an example context in which the cable winch system installedon a landing string may be implemented. The description herein shouldnot be understood as limiting the applicability of the cable winchsystem to a particular context and/or system, however.

A wireline blow out preventer (BOP) 110 and a flowhead 120, may belocated at, near or above the sea's surface. Additionally,hydraulic/electrical consoles 132 and a chemical injection skid 134 maybe positioned on a rig floor 130 at, near or above the surface.Communication and control modules may be located on the rig floor aswell and may be configured to communicate with and/or control subseacomponents.

Lubricator valves 140 may be located beneath the rig and within a riser150. Tubing may extend within the riser 150 and through a subsea BOPstack 170, a subsea test tree 180 and below a mudline 190. One or moresafety valves 192 may be located below the mudline along with drill stemtesting (DST)/completion string components 194.

FIG. 2 illustrates the cable winch system 200 that may be implementedwith the system of FIG. 1. The cable winch system 200 includes a winch220 with a communications cable 208, such as a fiber optic or copperbased communications cable. The winch 220 may be located subsea insidethe riser 150. The cable 208 may be paid out under tension as thelanding string is deployed. The cable diameter can be configured to havea size, such as approximately ⅜″ or less, to accommodate spacerestraints within the riser annulus. In other embodiments, the cable maybe approximately ⅜″ or larger.

The cable 208 can be fixed on the rig floor 130 at a termination point206. For example, the termination point 206 may be at or near a surfacelocation such as at or near a rig's rotary table. This may help preventcable damage due to rubbing on slips. Additionally, no overhead sheavesmay be implemented to route the cable to the winch and not added deckspace may be consumed by the winch. Relative motion between the cableand the riser or landing string tubular is reduced, and may beeliminated in some instances.

A master control station 202 may be communicatively coupled with thecable termination point 206. For example, in one embodiment, a jumper204, such as an armored jumper, can be utilized to connect the cabletermination point 206 to the master control station 202. The jumper isinstalled from the cable termination 206 using a connector to attach thejumper or the jumper can be an extension of the cable. The jumper is ofsufficient length to account for the relative motions when the cable isclamped to the landing string tubular and the jumper may be flexible.The jumper cable (or cable extension) can include a connector whichmates with a compatible receptacle on the Master Control Station 202. Insome embodiments, a wireless communication link may be provided betweenthe master control station 202 and the cable termination 206. In suchembodiments, a communication node may be co-located with the cabletermination 206. The communication node may take any suitable form andmay include one or more antennas. Additionally, one or moretransmitters/receivers and/or other components, such as signalprocessing components, may be co-located with the cable terminationand/or the master control station. For example, a multiplexer, a filter,an amplifier and so forth each may be provided.

In one embodiment, the winch 220 may include a standard configurationwith a grooved sleeved drum, level wind subassembly 211, slip rings 230for communications and power and interface to the landing stringcontrols 212 via a subsea jumper cable 210. The winch 220 can beelectrically operated from the subsea test tree 180 (FIG. 1) orhydraulically powered from a subsea hydraulic power unit (HPU).

The winch 220 may be controlled automatically using tension controlsthat set a constant or variable tension at the winch. The tensioncontrol system 231 may automatically compensate for the amount of cablepaid out during deployment into and out of the riser. This load keepsthe cable taut so that it does not fall into the riser 150, snag on theriser or bird nest on the drum. The set tension allows the winch to payout cable when tubulars 160 are lowered or pay in cable when tubularsare raised. Winch drum inertia may be mitigated to provide for propertension control and operation. Further, the winch 220 can include alevel wind system 211 to help spool cable onto the drum.

The subsea winch cable 208 may have a standard configuration with aramidfiber strength member over a water proof jacket containing theconductor(s) or may have a metal outer strength member. The conductorsmay be used for control signal and or power as required within theconstraints of the cable diameter.

The cable 208 can include a tension termination to be connected at therig floor or above (e.g., the termination point 206). This tensiontermination may be located at the surface end of the cable and isclamped off to a structural member on the rig floor or above. Becausethe rig is moving relative to the seafloor the winch compensates for therelative motion when the landing string is installed. To avoid therelative motion, after installation, a connection may be made bytransferring the termination to a clamp on the landing string tubular.

Some embodiments may take the form of a method of deploying cable from alanding string as it is deployed. For example, once the equipment isplaced on the rig, and as the landing string is deployed into the riser150, the cable end is connected to the rotary. A guide roller assemblymay be installed in the rotary when the landing string is in the riserto move the termination away from the rotary slips 240. A surface jumper204, which connects the cable 208 to the master control station 202, isthen connected to the cable safely.

As successive tubular strings are connected and the landing string isdeployed in the riser 150, the subsea winch 220 automatically pays outcable 208 during deployment and maintains tension at the winch. When thecable 208 is fully deployed the cable may be connected to the landingstring tubular so that any vessel motion does not affect the cable. Insome embodiments, the jumper 204 is provided with slack to take vesselmotion. In some embodiments, no topside swivel associated with thesystem is provided. As such, any rotation can be taken out by slack inthe cable. Further, the winch 220 is configured to automatically pay incable 208 during retrieval operations. Since there is not a requirementto attach the umbilical to the landing string tubulars during operationsthis method presents a time savings over existing techniques.

While various embodiments have been described herein with respect to alimited number of examples, those skilled in the art, having benefit ofthis disclosure, will appreciate that other embodiments and variationsthereof can be devised which do not depart from the scope disclosedherein. Accordingly, the scope of the claims should not be unnecessarilylimited by the present disclosure.

What is claimed is:
 1. A system comprising: a tubular deployable withina riser; and a cable winch deployable within a riser, wherein the cablewinch is configured to travel with the tubular as it is deployed withinthe riser.
 2. The system of claim 1, wherein the cable spool dispensescable as it is deployed within the riser.
 3. The system of claim 2,wherein the cable is deployed under tension.
 4. The system of claim 2,wherein the cable comprises at least one of a fiber optic cable or acopper based cable.
 5. The system of claim 2, wherein the cable isterminated at or near a rig floor.
 6. The system of claim 4, wherein aflexible jumper communicatively couples the cable with a surface controlsystem.
 7. The system of claim 4, wherein a flexible jumpercommunicatively couples the cable with a subsea control system.
 8. Thesystem of claim 3, wherein a hydraulic, electrical or hydroelectricaldevice provides tension.
 9. The system of claim 8, wherein thehydraulic, electrical or hydroelectrical device is configured tocompensate for relative motion between a rig at surface and the


10. The system of claim 1 further comprising a guide roller assemblyinstalled in a rotary.
 11. The system of claim 2, wherein the cable isapproximately ⅜″ cable or less.
 12. The system of claim 2, wherein thecable is approximately ⅜″ cable or greater.
 13. The system of claim 1,wherein the cable winch comprises a level winding system.
 14. A methodof providing subsea communications comprising: securing a cable winch toa subsea landing string; securing a cable wound on the cable winch at asurface location; and deploying the subsea landing string.
 15. Themethod of claim 14 further comprising: communicatively coupling thecable with subsea controls; and communicatively coupling the cable witha master control system.
 16. The method of claim 15, wherein a firstjumper is coupled between a cable termination and the subsea controlsand a second jumper is coupled between a cable termination at surfaceand the master control system.
 17. The method of claim 14 furthercomprising clamping an end of the cable to a landing string tubularafter installation to eliminate relative motion between the cable andthe landing string.
 19. The method of claim 14, further comprisingproviding tension to the cable as the landing string is deployed. 20.The method of claim 14, further comprising: retrieving the landingstring; and winding cable onto the winch.